Ratios de Sharpe ; variables explicatives et cibles

Machine Learning pour la finance en Python

Nathan George

Data Science Professor

meilleurs portefeuilles

meilleurs portefeuilles avec point de Sharpe

équation du ratio de Sharpe

Calculer nos ratios de Sharpe

# empty dictionaries for sharpe ratios and best sharpe indexes by date
sharpe_ratio, max_sharpe_idxs = {}, {}

# loop through dates and get sharpe ratio for each portfolio
for date in portfolio_returns.keys():
    for i, ret in enumerate(portfolio_returns[date]):
        volatility = portfolio_volatility[date][i]
        sharpe_ratio.setdefault(date,[]).append(ret / volatility)

    # get the index of the best sharpe ratio for each date
    max_sharpe_idxs[date] = np.argmax(sharpe_ratio[date])

Créer des variables explicatives

# calculate exponentially-weighted moving average of daily returns
ewma_daily = returns_daily.ewm(span=30).mean()

# resample daily returns to first business day of the month
ewma_monthly = ewma_daily.resample('BMS').first()

# shift ewma 1 month forward
ewma_monthly = ewma_monthly.shift(1).dropna()

Calculer variables explicatives et cibles

targets, features = [], []


# create features from price history and targets as ideal portfolio
for date, ewma in ewma_monthly.iterrows():
    # get the index of the best sharpe ratio
    best_idx = max_sharpe_idxs[date]
    targets.append(portfolio_weights[date][best_idx])
    features.append(ewma)

targets = np.array(targets)
features = np.array(features)

# latest date
date = sorted(covariances.keys())[-1]

cur_returns = portfolio_returns[date]
cur_volatility = portfolio_volatility[date]

plt.scatter(x=cur_volatility,
            y=cur_returns,
            alpha=0.1,
            color='blue')

best_idx = max_sharpe_idxs[date]

plt.scatter(cur_volatility[best_idx],
            cur_returns[best_idx],
            marker='x',
            color='orange')
plt.xlabel('Volatility')
plt.ylabel('Returns')
plt.show()

frontière efficiente avec Sharpe

Optimisez avec Sharpe !

Machine Learning pour la finance en Python